Genetic engineering has allowed the improvement of microorganisms used as industrial bioreactors, cell factories and in food fermentations. In particular, Bacillus species produce and secrete a large number of useful proteins and metabolites (Zukowski, “Production of commercially valuable products,” In: Doi and McGlouglin (eds.) Biology of Bacilli: Applications to Industry, Butterworth-Heinemann, Stoneham. Mass pp 311-337 [1992]). The most common Bacillus species used in industry are B. licheniformis, B. amyloliquefaciens and B. subtilis. Because of their GRAS (generally recognized as safe) status, strains of these Bacillus species are natural candidates for the production of proteins utilized in the food and pharmaceutical industries. Important production enzymes include α-amylases, neutral proteases, and alkaline (or serine) proteases. However, in spite of advances in the understanding of production of proteins in Bacillus host cells, there remains a need for methods to improve the expression and production of these proteins by microorganisms.